Method of manufacturing shochu

ABSTRACT

This invention&#39;s method of manufacturing shochu consists of the following steps: (1) cultivating koji mold ( Aspergillus oryzae ) upon and into steamed rice, (2) making starter mash by fermenting a mixture of the koji mold, yeast seeds, and water, (3) making mash by fermenting a mixture of the starter mash, steamed vegetable(s), and water containing 300 mg/kg-1,000 mg/kg of hydrogen carbonate ions, (4) filtrating said mash in order to separate its solid and liquid parts, and (5) distilling said liquid. Milk can be used in the fermentation process.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method of manufacturing shochu, atraditional Japanese distilled spirit, and more particularly to shochuthat has a characteristic taste and aroma.

BACKGROUND ART

Shochu is manufactured by fermenting one or more vegetables such asrice, wheat, millet, corn, sweet potatoes, or potato buckwheat by usingkoji mold and yeast and then distilling the mixture.

It is well-known that the taste and aroma of shochu is greatlyinfluenced by the type of vegetable(s) used as the raw material(s) to befermented, the water used for fermentation, and the fermentationconditions.

Although every type of shochu has a taste, something attractive must beadded to get people to choose it in competitions with various otherkinds of alcoholic beverages that are available on the market.Therefore, variations and uniqueness in the taste and aroma of shochuare always desired.

Responding to these needs, some new raw materials and some newmanufacturing processes for shochu have been proposed, as described inthe literature; these include, for example, shochu that is made usinglactic-acid bacteria that is added in the fermentation stage (JapanesePublished Unexamined Patent Applications No. 060531/00), shochu that ismade using cow milk that is added in the fermentation stage (JapanesePublished Unexamined Patent Applications No. 132173/86, No. 108971/89,No. 17154/01), and shochu that is made using ionized alkaline water(Japanese Published Unexamined Patent Applications No. 345450/02).

DISCLOSURE OF THE INVENTION

The objective underlying the present invention is to provide shochu thathas a unique and distinguishing taste and aroma.

Accordingly, one object of the present invention is to manufactureshochu by the following steps:

-   -   1.cultivating koji mold (Aspergillus oryzae) upon and into        steamed rice,    -   2. making starter mash by keeping a first mixture, comprising        said koji mold, yeast seeds, and water containing 300        mg/kg-1,000 mg/kg of hydrogen carbonate ions, at 20° C.-35° C.        for 1 day-4 days,    -   3. making mash by fermenting a second mixture comprising said        starter mash, one or more steamed vegetables, and additional        water containing 300 mg/kg-1,000 mg/kg of hydrogen carbonate        ions,    -   4. filtrating said mash in order to separate its solid and        liquid parts, and    -   5. distilling said liquid part.

Another objective of the present invention is to provide shochu that ismade by adding milk as a part of or instead of the above-mentioned waterfor use in fermentation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart that illustrates the general process formanufacturing shochu.

BEST MODE FOR CARRYING OUT THE INVENTION

The general process for manufacturing shochu will now be described withreference to FIG. 1.

The first step is a koji-cultivating step in which spores of koji mold(Aspergillus oryzae) are sprinkled over steamed rice and cultivated uponand into the rice (Step 1).

Fermentation is carried out in two stages. The first is apre-fermentation stage in which the koji mold and a small amount ofyeast are put into water and the resulting mixture is kept at 20° C.-35°C., preferably at 25° C.-30° C., for 1 day-4 days, and preferably for 2days-4 days (Step 2). The highest priority in making starter mash is toincrease the number of yeast cells. Therefore the temperature and thelength of time should be decided upon based on the extent of yeastgrowth that is desired.

Subsequently the main fermentation stage begins with the additions ofone or more steamed vegetables and additional water to thepre-fermentation mixture so as to give a mash (Step 3). Thisfermentation stage typically takes 1 week to 2 weeks at 25° C.-30° C.The vegetables can be rice, wheat, millet, corn, sweet potatoes,potatoes, or buckwheat, or any combination thereof.

In manufacturing shochu, the koji mold breaks down the steamedvegetables' starch into fermentable sugars, and the yeast converts thesugars into ethanol.

After enough time has passed for the main fermentation stage to becompleted, the mash is separated into its solid and liquids (Step 4).The liquid is a crude shochu, which is aged for a time, if necessary,and then is distilled under an atmospheric or vacuum conditions (Step5).

The distilled, refined shochu, is diluted with water so as to adjust thealcohol content to a level suitable for drinking, after which it isbottled (Step 6).

As mentioned above, the vegetables are saccharized with koji mold andthe saccharides in the vegetables are fermented in the presence ofyeast, which chemically means that carbohydrates are biodegraded intoethanol and small amounts of other alcohols, carboxylic acids, esters,and aldehydes. Each of these minor ingredients gives the manufacturedshochu a characteristic taste and aroma. The taste and aroma of thefinished product depend on the constitutions of those minor ingredients,which depend on the kind of vegetables used and the fermentationconditions.

The present invention uses a specific water that contains a large amountof hydrogen carbonate ions for the fermentation. The content of thehydrogen carbonate ions in the water is 300 mg/kg-1,000 mg/kg,preferably 400 mg/kg-600 mg/kg. Negative ions other than hydrogencarbonate ions can be used in this invention although the total contentof negative ions other than hydrogen carbonate ions normally is lessthan 200 mg/kg. However, the presence in the water of positive ions assodium ions, potassium ions, calcium ions, magnesium ions, ammoniumions, aluminum ions, iron ions, lithium ions, barium ions, zinc ion, andmanganese ions is not limited, so long as they do not have any adverseeffects on the shochu of this invention. Typically positive ions in thewater are 200 mg/kg-800 mg/kg of sodium ions, 30 mg/kg-400 mg/kg ofpotassium ions, 2 mg/kg-50 mg/kg of calcium ions, 0.1 mg/kg-20 mg/kg ofmagnesium ions, and less than 1 mg/kg of other ions. Water containing alarge amount of hydrogen carbonate ions can be obtained naturally or bythe addition of hydrogen carbonate salts such as sodium hydrogencarbonate, potassium hydrogen carbonate, or calcium hydrogen carbonate.

The presence of hydrogen carbonate ions in the water has a great effecton the fermentation products, the amount of each of the products, andtheir composition. The fermentation products are, as mentioned above,alcohols, carboxylic acids, esters, aldehydes, and other products, allof which deeply affect the taste and aroma of the shochu. Typicalproducts are described below in the subsection entitled “Example 2.”

The shochu of the present invention is manufactured in the usual way,except that the water that is used contains a specified content ofhydrogen carbonate ions as a result of the pre-fermentation and mainfermentation processes. Also, water that contains hydrogen carbonateions can be used for the dilution water used to adjust the alcoholcontent of the finished product.

The present invention can utilize milk as a part of or instead of thewater that is added in the main fermentation step. The milk can be cowmilk, goat milk, ewe milk, or any blend thereof The amount of milkshould be less than 1.5 times the weight—preferably 0.5-1.0 times theweight—of the total amount of water added in the pre-fermentation andmain fermentation stages. If the amount of milk exceeds 1.5 times theweight of the water, the taste and aroma of the finished shochu can beunsatisfactory. The milk is added before the main fermentationsubstantially starts.

The additions of milk in the fermentation process slightly changes theactivities of the yeast, due to the presence of the animal fats andprotein contained in milk. The additions of milk sometimes has anadverse effect on the taste and aroma., as noted above The literature ofJapanese Published Unexamined Patent Applications No. 108971/89, forexample, indicates that pH adjustment and heat sterilization in theprocess are necessary in order to prevent the taste and aroma to bedeteriorated due to the decomposition of the milk. The presentinvention, in contrast, can bring out a distinct taste and aroma to theshochu by using milk with a specified water for the fermentation. Thisunique aroma is one of characteristic features that differentiates theshochu of this invention from other conventional shochu that isavailable on the market.

EXAMPLES

The following examples are presented to indicate the preferredembodiments and utility of the invention, and the examples are notintended to limit the invention unless otherwise stated in the claimsappended hereto.

Example 1

The shochu of this example was manufactured in the conventional wayexcept that specific water containing a large amount of hydrogencarbonate ions was used in the fermentation. For this example, 100 kg ofkoji mold, a small amount of yeast, and 150 kg of water that contained500.4 mg/kg of hydrogen carbonate ions were put into a tank, mixed well,and kept at 20° C.-25° C. for 3 days in order to make a starter mash.Then 400 kg of steamed rice and 300 kg of the same quality of water asmentioned above were added to the starter mash, mixed well, and kept at25° C.-33° C. for 10 days. After filtration, the liquid was distilled.The distillate contained approximately 40% alcohol, and it was dilutedwith water to 25% alcohol. Table 1 shows the types and amounts of ionsin the water of this example. TABLE 1 Ions Composition of the Water Usedfor Example 1 Type of Ions Formula Amount Used Hydrogen carbonate ions(HCO³⁻) 500.4 mg/kg  Sodium ions (Na⁺) 250.5 mg/kg  Potassium ions (K⁺)51.4 mg/kg  Calcium ions (Ca⁺) 5.6 mg/kg Magnesium ions (Mg⁺) 0.6 mg/kgAluminum ions (Al⁺) 0.1 mg/kg

The taste and aroma of the shochu that was obtained were evaluated by 15judges, all of whom were alcoholic-beverage specialists. They concludedthat the shochu was as fruity as if it were a fruits wine or made fromfruits. This clearly differentiates the product of this invention fromconventional shochu.

Example 2

To the same starter mash as described above for use in Example 1, therewas added 400 kg of steamed rice, 300 kg of the same water used inExample 1, and 400 kg of milk. The mixture was kept at 25° C.-33° C. for8 days for fermentation. The judges rated the aroma of the shochuobtained in this example as superior to that of the shochu of Example 1.In addition, the minor ingredients of said shochu were analyzed bygas-chromatography. The results of that analysis are shown by Table 2.TABLE 2 Minor Ingredients (ppm) in the Shochu of Example 2 and in ThreeOther Shochu Products on the Market Shochu of the Present inventionProduct A Product B Product C Acetaldehyde 20.005 10.622 13.486 15.885Ethyl acetate 52.258 47.287 53.017 54.319 Isobutyl acetate 0.355 0.3660.512 0.552 n-Propyl alcohol 256.589 126.195 125.522 135.001 Isobutylalcohol 198.897 211.253 223.012 184.785 Isoamyl acetate 4.768 9.64310.470 11.710 Isoamyl alcohol 575.135 418.170 420.544 362.043 Ethylcaproate 7.473 0.433 0.580 0.687 β-Phenethyl Alcohol 70.128 26.11448.756 22.569 Ethyl caprylate 0.080 0.006 0.013 0.013 Ethyl caprate0.049 — 0.002 0.002 β-Phenethyl acetate 0.053 0.049 0.071 0.023 Ethyllaurate — — 0.001 0.007 Ethyl myristate — — — 0.003

The results confirmed that the shochu of this example contained a largermuch amount of ethyl caproate, β-phenethyl alcohol, ethyl caprylate, andethyl caprate than did Shochu A, Shochu B, and Shochu C, which wereshochu products available on the market, and which were manufacturedfrom the same raw materials as in the present invention's shochu, exceptfor the water. These ingredients are regarded as characteristic of theshochu of the present invention.

Example 3

The shochu of Example 3 was manufactured by the same procedure as thatof Example 2, except that steamed sweet potatoes were used instead ofrice for the main fermentation stage. The shochu obtained had a uniquearoma that is distinguishable from that of conventional shochu.

INDUSTRIAL APPLICABILITY

The present invention has an unique aroma regardless of the method ofmaking it, which differs little from the method of making standardshochu, and the aroma can differentiate this shochu from other shochuproducts, and the shochu of the present invention is unique among manyshochu products.

1. A shochu manufacturing method that consists of the following steps:(a) cultivating koji mold (Aspergillus oryzae) upon and into steamedrice; (b) making starter mash by keeping a first mixture, which consistsof said koji mold, yeast seeds, and water that contains 300 mg/kg-1,000mg/kg of hydrogen carbonate ions, at 20° C.-35° C. for 1 day-4 days; (c)making mash by fermenting a second mixture, which consists of saidstarter mash, one or more steamed vegetables, and additional watercontaining 300 mg/kg-1,000 mg/kg of hydrogen carbonate ions; (d)filtrating said mash in order to separate its solid and liquid parts;and (e) distilling said liquid.
 2. Shochu according to claim 1, butwherein said vegetable(s) is/are selected from a group that consists ofrice, wheat, millet, corn, sweet potatoes, potatoes, and buckwheat, oris any combination thereof.
 3. Shochu according to claim 1, but whereinmilk is added to said second mixture as a part of or instead of thewater containing 300 mg/kg-1,000 mg/kg of hydrogen carbonate ions. 4.Shochu according to claim 3, but wherein said milk is selected from agroup consisting of cow milk, goat milk, ewe milk, or is any combinationthereof
 5. Shochu according to claim 3, but wherein the amount of saidmilk is less than 1.5 times the weight of the total amount of wateradded to said first mixture and said second mixture.